Viewing Area Survey System
The viewing area survey system using an unmanned flying vehicle simplifies and accelerates the determination of radio wave viewing areas by automating measurements, reducing time and costs through autonomous or remote control.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- JAPAN RADIO CO LTD
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
AI Technical Summary
Conventional methods for determining the viewing area of a radio wave require time-consuming manual adjustments and extensive vehicle-based measurements, leading to high costs and inefficiencies.
A viewing area survey system utilizing an unmanned flying vehicle equipped with position, altitude, and received electric field strength measurement means, allowing for autonomous or remotely controlled flight to determine the viewing area by acquiring points with minimum required electric field strength.
Reduces measurement preparation time and effort, enabling easy and efficient determination of the viewing area by simplifying the measurement process and allowing flexible surveying even in challenging conditions.
Smart Images
Figure 2026092260000001_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a technique for determining the viewing area of a predetermined radio wave based on the measurement of the received electric field strength.
Background Art
[0002] Due to the shift of television broadcasting from analog to digital, various multimedia broadcasts have come to be conducted in the vacant VHF band. Along with this, the need to address interference and insufficient received electric field strength has increased, and received electric field strength measurements are being carried out at various locations to examine the radio wave propagation state (see Patent Document 1).
[0003] Conventionally, an electric field strength measuring device was loaded on an electric measurement vehicle and driven, and the received electric field strength of radio waves was individually measured manually at the measurement planned locations. Specifically, as shown in FIG. 6, the antenna 101 was supported by a plurality of combined support rods 103 (for example, each having a length of 1 m), and a human 105 held this by hand and measured the received electric field strength at a desired height.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, the conventional method takes time for measurement preparation, such as attaching the support rod 103 to the antenna 101 for measurement, and the height of the antenna 101 has to be adjusted by the number of combinations of the support rods 103 and the height of the hand holding this in order to measure at a certain height, and the measurement of the received electric field strength is complicated.
[0006] Furthermore, determining the reception area for a given radio wave required driving around in a vehicle equipped with a field strength measuring device, stopping at multiple measurement points to set up the device, and taking measurements. This meant that a great deal of time and effort was spent on surveying the reception area, resulting in high costs.
[0007] Therefore, the present invention aims to provide a viewing area survey system that enables easy measurement of the received electric field strength for determining a viewing area for a given radio wave. [Means for solving the problem]
[0008] To solve the above problems, the invention described in claim 1 is a viewing area survey system comprising: a position detection means mounted on an unmanned flying vehicle that detects the position information of the vehicle; an altitude measuring means mounted on the vehicle that measures the altitude of the vehicle; a received electric field strength measuring means mounted on the vehicle that measures the received electric field strength of a predetermined radio wave; and a viewing area determination means that determines the viewing area of the predetermined radio wave, wherein the position detection means, the altitude measuring means, and the received electric field strength measuring means are communicated with each other; the vehicle flies based on a predicted viewing area where the received electric field strength of the predetermined radio wave is predicted to be equal to or greater than the minimum received electric field strength required to view the predetermined radio wave, thereby acquiring a point where the received electric field strength of the predetermined radio wave measured by the received electric field strength measuring means becomes the minimum received electric field strength; and the viewing area determination means determines the area inside the area formed by connecting the acquired points as the viewing area.
[0009] The invention described in claim 2 is a viewing area survey system according to claim 1, comprising a remote control means for remotely controlling the flight of the aircraft, wherein the position detection means, the altitude measuring means, and the received electric field strength measuring means are communicated with each other, and if the aircraft cannot acquire a point where the received electric field strength of the predetermined radio wave becomes the minimum received electric field strength, the remote control means remotely controls the flight of the aircraft. [Effects of the Invention]
[0010] According to the invention of claim 1, the received electric field strength can be measured at a constant altitude simply by flying an aircraft, thus reducing the time and effort required for measurement preparation that was previously necessary, and making it possible to easily measure the received electric field strength. Furthermore, in order to determine the viewing area of the radio wave to be investigated, it is only necessary to fly an aircraft equipped with a received electric field strength measuring means and acquire the point that has the minimum received electric field strength required to view that radio wave, thereby significantly reducing the time and effort required to investigate the viewing area, and making it possible to easily determine the viewing area.
[0011] Furthermore, according to the invention of claim 2, even if the aircraft is unable to acquire a point with the minimum received electric field strength necessary for viewing the radio waves to be investigated through autonomous flight, it can switch to remotely controlled flight and continue measurements, making it possible to conduct surveys of the viewing area flexibly according to the situation. [Brief explanation of the drawing]
[0012] [Figure 1] This is a block diagram showing the schematic configuration of the viewing area survey system according to Embodiment 1 of the present invention. [Figure 2] This is a flowchart showing the procedure for measuring the received electric field strength in the viewing area survey system according to Embodiment 1 of this invention. [Figure 3](A) A diagram showing an aircraft and measuring device used in the viewing area survey system according to Embodiment 1 of this invention, and (B) a diagram showing the predicted viewing area of a predetermined radio wave and its outer edge (boundary line) to be referenced in the viewing area survey. [Figure 4] This is a block diagram showing the schematic configuration of a management server used in the viewing area survey system according to Embodiment 2 of this invention. [Figure 5] This is a flowchart showing the procedure for measuring the received electric field strength in the viewing area survey system according to Embodiment 2 of this invention. [Figure 6] This is a diagram illustrating a conventional method for measuring electric field strength. [Modes for carrying out the invention]
[0013] The present invention will be described below based on the illustrated embodiments.
[0014] (Embodiment 1) Figure 1 is a block diagram illustrating the schematic configuration of the viewing area survey system 1 according to Embodiment 1 of the present invention. The viewing area survey system 1 is a system primarily for surveying the viewing area of broadcast waves such as radio, and comprises a measuring device 3 for measuring the received electric field strength of the radio waves to be surveyed, a drone (flying object) 2 (see Figure 3A) that carries the measuring device 3 and flies, and a management server 4 that determines the viewing area based on the measurement results (measurement data) obtained by the measuring device 3. The measuring device 3 and the management server 4 are connected to each other so as to be able to communicate with each other. In this embodiment, the case in which the target of the survey is a predetermined broadcast wave (hereinafter referred to as "broadcast wave A") will be mainly described, but radio waves such as those for broadcast radio and telemetry may also be used as the target of the survey.
[0015] Here, the viewing area for broadcast wave A can be predicted (simulated) using the minimum received electric field strength required to receive broadcast wave A. Figure 3B shows the predicted viewing area EA for broadcast wave A based on this prediction, and the outer edge (boundary line) EL of the predicted viewing area (i.e., a line connecting the points where the received electric field strength of broadcast wave A is predicted to be the minimum received electric field strength). It is necessary to verify (investigate) whether the predicted viewing area EA is appropriate by actually measuring the received electric field strength of broadcast wave A. The viewing area investigation system 1 of the present invention is a system used for such investigations.
[0016] Drone 2 is an unmanned aerial vehicle, and in this embodiment, it is equipped with a measuring device 3 and is configured to autonomously fly along a predetermined flight path. Specifically, it confirms its own position using a GNSS (Global Navigation Satellite System) device (position detection means) 31 provided on the measuring device 3, and autonomously controls its flight while confirming its own altitude using an altimeter (altitude detection means) 32 provided on the measuring device 3. In this case, the drone 2 may be programmed in advance to define a flightable area, thereby limiting its flight range.
[0017] The measuring device 3 (see Figure 3A) mounted on the drone 2 mainly comprises a GNSS device 31, an altimeter 32, a received field strength measuring unit (received field strength measuring means) 33, a communication unit 34, a storage unit 35, a flight control unit 36, and an antenna 37. In this embodiment, the GNSS device 31, altimeter 32, received field strength measuring unit 33, communication unit 34, storage unit 35, flight control unit 36, and antenna 37 are provided on the measuring device 3, but each unit (each device) 31 to 37 may also be directly mounted on the drone 2 body.
[0018] The GNSS device 31 is a device for receiving GNSS radio waves transmitted from GNSS satellites via the antenna 37, demodulating them to extract GNSS signals, and detecting position information indicating the current position of the drone 2 included in the GNSS signals. This position information is represented by longitude and latitude. The position information of the drone 2 detected by the GNSS device 31 is stored in the storage unit 35 and sent to the communication unit 34.
[0019] The altimeter 32 is a device for measuring the altitude of the current position of the drone 2 and is a device required for measuring the received electric field strength at a constant altitude. That is, when investigating the viewing area of the broadcast wave A, the received electric field strength must be measured at a constant altitude. By checking the altitude of the drone 2 with the altimeter 32, it becomes possible to measure the received electric field strength at a constant altitude. Instead of the single altimeter 32, a GNSS device 31 with an altimeter may be used. The altitude of the drone 2 measured by the altimeter 32 is stored in the storage unit 35 and sent to the communication unit 34.
[0020] The received electric field strength measurement unit 33 is a device for measuring the received electric field strength of the broadcast wave A. The measurement by the received electric field strength measurement unit 33 is performed at a constant altitude while flying the drone 2 or in a stopped state (while hovering). The received electric field strength of the broadcast wave A measured by the received electric field strength measurement unit 33 is stored in the storage unit 35 and sent to the communication unit 34.
[0021] The communication unit 34 is an interface for communicating with the outside world via a communication network such as an internet line, and communicates with the management server 4. In this embodiment, the communication unit 34 receives the broadcast wave A and transmits to the management server 4 the position information of the drone 2 detected by the GNSS device 31, the altitude of the drone 2 measured by the altimeter 32, and the received field strength of the broadcast wave A measured by the received field strength measurement unit 33. The format and timing of transmitting this information (measurement data) to the management server 4 can be set as appropriate. For example, this information (measurement data) can be bundled together into an IP packet and transmitted (output) to the management server 4, or it can be transmitted (output) separately. Furthermore, this information (measurement data) can be transmitted (output) to the management server 4 in real time each time the received field strength measurement unit 33 performs a measurement, or it can be transmitted (output) at a predetermined timing, or it can be transmitted (output) when the measurement by the measurement device 3 is completed. These pieces of information (measurement data) transmitted (output) to the management server 4 are received by the communication unit 43 (described later) and sent to the viewing area determination unit (viewing area determination means) 46.
[0022] The memory unit 35 is a device that stores data necessary for programs and various processes. In this embodiment, the memory unit 35 stores, for example, the flight path provided by the management server 4 (described later), the position information of the drone 2 detected by the GNSS device 31, the altitude of the drone 2 measured by the altimeter 32, and the received field strength of broadcast wave A measured by the received field strength measurement unit 33.
[0023] The flight control unit 36 is a device that controls the flight of the drone 2. Specifically, it controls the flight of the drone 2 so that it can autonomously fly along a flight path, perform tracking flight, or terminate flight based on the measurement results (measurement data) of the received electric field strength of broadcast wave A, as will be described later.
[0024] The management server 4 is a server computer for determining the viewing area of broadcast wave A using measurement results (measurement data) such as the received field strength of broadcast wave A by the drone 2. The management server 4 mainly comprises an input unit 41, a display unit 42, a communication unit 43, a storage unit 45, a viewing area determination unit 46, and a central processing unit 44 that controls these. The management server 4 is installed, for example, at a base station or a radio measurement vehicle used for viewing area surveys.
[0025] The input unit 41 is an interface for inputting various information and commands, specifically for inputting the flight path that the drone 2 will refer to when flying. The flight path that the drone 2 will refer to when flying is set based on the predicted viewing area EA of broadcast wave A (i.e., the area where the received field strength of broadcast wave A is predicted to be equal to or greater than the minimum received field strength of broadcast wave A). In other words, the flight path is input by specifying the route that the drone 2 will refer to when flying on a map in which the predicted viewing area EA of broadcast wave A is stored.
[0026] Here, the predicted viewing area EA for broadcast wave A is approximately circular due to the characteristics of radio wave propagation (see Figure 3B). It is assumed that there are points on the outer edge (boundary) EL of this predicted viewing area where the received electric field strength of broadcast wave A is predicted to be the minimum received electric field strength, and that there are points within the predicted viewing area EA where the received electric field strength of broadcast wave A is predicted to be equal to or greater than the minimum received electric field strength. Therefore, the line connecting the outer edge (boundary) EL of the predicted viewing area, that is, the points where the received electric field strength of broadcast wave A is predicted to be the minimum electric field strength, will be set as the flight path that drone 2 will refer to. The predicted viewing area EA for broadcast wave A can be obtained by simulation using a known program.
[0027] The display unit 42 is a display that shows various data and information, specifically the map mentioned above, the predicted viewing area EA, the flight path, and the results of the viewing area determination unit 46 (the viewing area of the determined broadcast wave A).
[0028] The communication unit 43 is an interface for communicating with the outside world via a communication network such as an internet line, and communicates with the measuring device 3 mounted on the drone 2. The storage unit 45 is a device that stores programs and data necessary for various processes. In this embodiment, the communication unit 43 receives (acquires) the measurement data from the measuring device 3 (specifically, the position information of the drone 2 at each measurement point, altitude, and the received field strength of broadcast wave A) and stores it in the storage unit 45. The storage unit 45 also stores information about broadcast wave A (including the viewing area determined by the viewing area determination unit 46).
[0029] The viewing area determination unit 46 is a program task that determines the viewing area for broadcast wave A based on the received electric field strength of broadcast wave A measured by the measuring device 3. The viewing area for broadcast wave A refers to the area where broadcast wave A can actually be viewed, and is defined as the area where the measured received electric field strength of broadcast wave A is equal to or greater than the minimum received electric field strength.
[0030] The viewing area determination unit 46 is activated when measurement data (specifically, the position information of the drone 2, the altitude of the drone 2, and the received field strength of broadcast wave A) is input from the measurement device 3 mounted on the drone 2. Then, once the measurement by the drone 2 (measurement device 3) is completed, the viewing area determination unit 46 uses these input measurement results (measurement data) to determine the viewing area of broadcast wave A.
[0031] Specifically, the viewing area determination unit 46 inputs the points obtained by the drone 2 as the points where the received electric field strength of broadcast wave A is at its minimum based on actual measurements, onto a map, and determines the area formed by connecting these obtained points (i.e., a roughly circular area with the lines connecting the obtained points as its outer edge (boundary)) as the viewing area for broadcast wave A.
[0032] Next, the procedure for measuring the received electric field strength in the viewing area survey system 1 will be explained using Figure 2.
[0033] Figure 2 is a flowchart showing the procedure for measuring the received electric field strength in the viewing area survey system 1 according to this embodiment. First, the system user inputs a roughly circular line connecting the outer edge (boundary line) EL of the predicted viewing area of broadcast wave A, that is, the point where the received electric field strength of broadcast wave A is predicted to be at its minimum, into the input unit 41 of the management server 4 as the flight path to be referenced. This flight path is then transmitted to the drone 2 (measuring device 3) via the communication unit 43 for storage (step S1).
[0034] When drone 2 is launched, it begins autonomous flight along this roughly circular flight path (step S2), and measures the received electric field strength, position, and altitude using the measuring device 3 at predetermined measurement points or predetermined measurement intervals (timing), and stores the measurement results (measurement data) in the storage unit 35 (step S3). The measuring device 3 may also transmit the measurement results (measurement data) to the management server 4 at this timing.
[0035] Next, the flight control unit 36 of the measurement device 3 determines whether the received electric field strength measured by the received electric field strength measurement unit 33 is the minimum received electric field strength at which broadcast wave A can be viewed (step S4). If it is the minimum received electric field strength (Yes in step S4), it further determines whether the measurement point is on the flight path, that is, whether it is on the outer edge (boundary line) EL of the predicted viewing area (step S5). If the measurement point is on the flight path (Yes in step S5), it causes the drone 2 to continue autonomous flight along the flight path (step S6).
[0036] On the other hand, if the measured received field strength is not the minimum received field strength of broadcast wave A (No in step S4), or if the measurement point is not on the flight path (No in step S5), it is considered that the outer edge (boundary) EL of the predicted viewing area is incorrect. Therefore, the flight control unit 36 switches the drone 2's flight to a tracking flight mode in which it autonomously flies while detecting the point where the received field strength of broadcast wave A becomes the minimum received field strength (step S7). The measurement device 3 stores the timing of the switch to tracking flight in the memory unit 35.
[0037] The flight control unit 36 makes decisions in steps S4 and S5 each time a measurement is taken. Therefore, for example, even if the drone 2 switches from autonomous flight along the flight path to tracking flight at a certain measurement point or time, it may return to autonomous flight along the flight path at another measurement point or time. By controlling the flight of the drone 2 in this way and measuring the received field strength of broadcast wave A, the predicted viewing area EA of broadcast wave A is corrected based on the actual measurement, and the actual viewing area of broadcast wave A is determined.
[0038] These series of measurement and flight control processes (steps S3 to S7) are repeated until the measurement by the measurement device 3 is completed. The measurement by the measurement device 3 is completed when it is determined that the drone 2 has completed one lap of a roughly circular flight path and returned to the vicinity of the measurement start point (Yes in step S8). The measurement device 3 may transmit the measurement results (measurement data) to the management server 4 when all measurements are completed. Due to the characteristics of radio wave propagation, it is thought that the drone will fly in a roughly circular path if it is flying while detecting a predetermined received electric field strength. Therefore, it is thought that the drone 2 will eventually return to the vicinity of the measurement start point not only when flying along the flight path, but also when it switches to tracking flight midway.
[0039] As explained above, with the viewing area survey system 1 according to this embodiment, the received electric field strength can be measured at a certain altitude simply by flying the drone 2, thus reducing the time and effort required for measurement preparation that was previously necessary, and making it possible to easily measure the received electric field strength. Furthermore, in order to determine the viewing area of broadcast wave A, it is only necessary to fly the drone 2 equipped with a received electric field strength measurement unit and acquire the point with the minimum received electric field strength required for viewing broadcast wave A, thereby significantly reducing the time and effort required for surveying the viewing area, and making it possible to easily determine the viewing area.
[0040] (Embodiment 2) Next, a description of the viewing area survey system 1 according to Embodiment 2 of the present invention will be provided. Note that the same reference numerals are used for components similar to those in Embodiment 1, and detailed explanations will be omitted.
[0041] This embodiment differs from Embodiment 1 in that, if the autonomous flight of the drone 2 cannot acquire the point where the received field strength of broadcast wave A is at its minimum, the management server 4 remotely controls the flight of the drone 2.
[0042] Figure 4 is a block diagram showing the schematic configuration of the management server 4 used in the viewing area survey system 1 according to this embodiment. The management server 4 further includes a remote control unit (remote control means) 47 to enable remote control of the drone 2.
[0043] The remote control unit 47 is a device that transmits control signals to remotely control the drone 2 and move it in a desired direction and position. The remote control unit 47 generates signals according to the operation of the input unit 41 by the system user and transmits the control signals to the drone 2 via the communication unit 43. Alternatively, instead of providing the remote control unit 47 on the management server 4, a remote control with the same functionality as the remote control unit 47 may be provided separately from the management server 4.
[0044] Next, the procedure for measuring the received electric field strength in the viewing area survey system 1 equipped with a remote control unit 47 will be explained using Figure 5.
[0045] Figure 5 is a flowchart showing the procedure for measuring the received electric field strength in this embodiment. First, the system user inputs a roughly circular line connecting the outer edge (boundary line) EL of the predicted viewing area of broadcast wave A, that is, the point where the received electric field strength of broadcast wave A is predicted to be at its minimum, into the input unit 41 of the management server 4 as the flight path to be referenced. This flight path is then transmitted to the drone 2 (measuring device 3) via the communication unit 43 for storage (step S1).
[0046] When drone 2 is launched, it begins autonomous flight along this roughly circular flight path (step S2), and measures the received electric field strength, position, and altitude using the measuring device 3 at predetermined measurement points or predetermined measurement intervals (timing), and the measurement results (measurement data) are stored in the storage unit 35 (step S3). The measuring device 3 may also transmit the measurement results (measurement data) to the management server 4 at this timing.
[0047] Next, the flight control unit 36 of the measurement device 3 determines whether the received electric field strength measured by the received electric field strength measurement unit 33 is the minimum received electric field strength at which broadcast wave A can be viewed (step S4). If it is the minimum received electric field strength (Yes in step S4), it further determines whether the measurement point is on the flight path, that is, whether it is on the outer edge (boundary line) EL of the predicted viewing area (step S5). If the measurement point is on the flight path (Yes in step S5), it causes the drone 2 to continue autonomous flight along the flight path (step S6).
[0048] On the other hand, if the measured received field strength is not the minimum received field strength of broadcast wave A (No in step S4), or if the measurement point is not on the flight path (No in step S5), it is considered that the outer edge (boundary line) EL of the predicted viewing area is incorrect. Therefore, the flight control unit 36 switches the drone 2's flight to a tracking flight, which autonomously flies while detecting the point where the received field strength of broadcast wave A becomes the minimum received field strength (step S7). Then, it determines whether the drone 2 can acquire the point where the received field strength of broadcast wave A becomes the minimum received field strength by performing the tracking flight (step S9), and if it can acquire it (Yes in step S9), it continues the tracking flight (step S10). The measurement device 3 stores the timing of the switch to tracking flight in the memory unit 35.
[0049] On the other hand, if tracking flight does not allow the drone to acquire a point where the received field strength of broadcast wave A is at its minimum (No in step S9), the flight control unit 36 interrupts the autonomous flight of the drone 2. If it is determined that remote control by the remote control unit 47 of the management server 4 is possible (Yes in step S11), the flight of the drone 2 is switched to remote control by the management server 4 (remote control unit 47) (step S12). On the other hand, if it is determined that remote control by the management server 4 (remote control unit 47) is impossible (No in step S11), for example, if the radio communication conditions are poor and the control signal from the management server 4 cannot reach the drone 2, the flight control unit 36 terminates the flight of the drone 2.
[0050] Drone 2 performs measurements at predetermined measurement points or at predetermined measurement intervals (timing), and makes decisions in steps S3 and S4 each time a measurement is taken. Furthermore, since the system is configured to make a decision in step S9 when it switches to tracking flight, even if Drone 2 becomes unable to measure the received field strength of broadcast wave A through autonomous flight, it can switch to remotely controlled flight based on instructions from the management server 4 (system user) and continue measurements. By controlling the flight of Drone 2 in this way and measuring the received field strength of broadcast wave A, the predicted viewing area EA of broadcast wave A is corrected based on the actual measurements, and the actual viewing area of broadcast wave A is determined.
[0051] These series of measurement and flight control steps (steps S3 to S12) are repeated until the measurement by the measuring device 3 is completed. The measurement by the measuring device 3 is completed when it is determined that the drone 2 has completed one lap of a roughly circular flight path and returned to the vicinity of the measurement start point (Yes in step S8). The measuring device 3 may also transmit the measurement results (measurement data) to the management server 4 when all measurements are completed.
[0052] As explained above, according to the viewing area survey system 1 of this embodiment, even if the drone 2 is unable to acquire a point with the minimum receiving field strength necessary for viewing broadcast wave A through autonomous flight, it can switch to remotely controlled flight and continue measurements, making it possible to conduct viewing area surveys flexibly according to the situation.
[0053] Although embodiments of this invention have been described above, the specific configuration is not limited to the embodiments described above, and any design changes that do not depart from the gist of this invention are also included in this invention. For example, a demodulator may be provided on the drone 2 to demodulate the received broadcast wave A into audio, and the audio data may be transmitted to the management server 4, so that the audio of broadcast wave A can be listened to and confirmed, or recorded, in a measuring vehicle equipped with the management server 4. [Explanation of Symbols]
[0054] 1. Viewing Area Survey System 2. Drone (flying object) 3. Measuring device 31 GNSS device (position detection means) 32 Altimeter (altitude measurement means) 33. Received electric field strength measurement unit (received electric field strength measurement means) 34 Communications Department 35 Storage section 36 Flight Control Unit 4. Management Server 41 Input section 42 Display section 43 Communications Department 44 Central Processing Unit 45 Storage section 46 Viewing Area Determination Unit (Viewing Area Determination Means) 47 Remote control unit (remote control means) EA Predicted Viewing Area EL Predicted Viewing Area Outer Edge
Claims
1. A position detection means mounted on an unmanned aerial vehicle for detecting the position information of the aerial vehicle, An altitude measuring means mounted on the aircraft for measuring the altitude of the aircraft, Mounted on the aforementioned aircraft, a receiving electric field strength measuring means for measuring the received electric field strength of a predetermined radio wave, The system includes a viewing area determination means for determining the viewing area of the predetermined radio waves, The position detection means, the altitude measuring means, and the received electric field strength measuring means are mutually communicatively connected to the viewing area determination means. The aircraft flies based on a predicted viewing area where the received electric field strength of the predetermined radio wave is predicted to be equal to or greater than the minimum received electric field strength required to view the predetermined radio wave, thereby acquiring a point where the received electric field strength of the predetermined radio wave, as measured by the received electric field strength measuring means, becomes the minimum received electric field strength. The viewing area determination means determines the area inside the area formed by connecting the acquired points as the viewing area. A viewing area survey system characterized by the following features.
2. The aircraft is equipped with remote control means for remotely controlling the flight of the aircraft, The position detection means, the altitude measuring means, and the received electric field strength measuring means are connected to the remote control means so as to be able to communicate with each other. If the aircraft cannot acquire a point where the received electric field strength of the predetermined radio wave is the minimum received electric field strength, the remote control means remotely controls the flight of the aircraft. The viewing area survey system according to feature 1.